Utility meter for use with distributed generation device

ABSTRACT

An integrated metering device allows a resource provider to control the output of a distributed generation device onto a resource distribution network or grid. The integrated metering device may include a communications module, a metrology module, an inverter and regulator device, and a transfer switch. A resource provider may communicate with the integrated metering device via the communications module and may control the inverter and regulator device or the transfer switch. The metrology module may monitor the energy provided by the distributed generation device to the grid and may send information about the generated energy to the resource provider via the communications module.

RELATED APPLICATIONS

This application claims priority to U.S. Ser. No. 15/606,314, filed May26, 2017 and entitled Utility Meter for Use with Distributed GenerationDevice, which claims priority to U.S. Ser. No. 62/342,005, filed May 26,2016 and entitled Utility Meter for Use with Distributed GenerationDevice, both of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a utility meter and in particular to anintegrated utility metering device that controls the flow of power froma distributed generation device onto a resource distribution grid.

BACKGROUND

An electric utility manages a distribution grid that delivers power toits customers. Typically, a meter is located at the customer's premiseswhich measures and controls the electricity delivered to the premisesvia the grid. The meter may be combined with a communications module sothat the meter can communicate with other meters and with the utility.The communications module may communicate via RF, cellular, PLC or anyother suitable communications technology.

In addition to delivering power, the grid may also accept powergenerated by devices at customer premises, such as that generated bysolar panels, wind mills, water turbines, and generators, collectivelyreferred to herein as distributed generation devices. Currently, thedevices used to connect these distributed generation devices to the gridare separate and distinct from the utility meter located at the customerpremises. They require additional installation and wiring and increasethe complexity of the connections to the grid. The utility may not havethe ability to control the distributed generation devices or theirconnections to the grid, which makes it challenging to manage the grid.

SUMMARY

An integrated metering device integrates the functions of an inverterand regulator device, a transfer switch, a utility meter, and adistributed generation meter into a single device. The integratedmetering device includes a communications module, a metrology module, aninverter and regulator device, and a transfer switch. The output of adistributed generation device, such as a solar panel or generator, isconnected to an input of the integrated metering device. The inverterand regulator device processes the output from the distributedgeneration device so that it meets the requirements of the grid. Atransfer switch controls the flow of energy generated by the distributedgeneration device onto the utility grid.

The metrology module may include a single metering device or multiplemetering devices. The metrology module may monitor the flow of energy toand from the grid, monitor the characteristics of the energy provided bythe distributed generation device, and control the transfer switch. Thecommunications module may receive communications via a network thatinclude instructions for controlling the inverter and regulator, thetransfer switch, or the metrology module. The communications module maytransmit information related to the operation of the integrated meteringdevice and the measurements taken by the metrology module to otherdevices on the network or a central system.

These illustrative aspects and features are mentioned not to limit ordefine the invention, but to provide examples to aid understanding ofthe inventive concepts disclosed in this application. Other aspects,advantages, and features of the present invention will become apparentafter review of the entire application.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates an exemplary network of metering devices, includingintegrated metering devices.

FIG. 2 illustrates an exemplary integrated metering device forconnecting a distributed generation device.

FIG. 3 illustrates a prior art system for connecting a distributedgeneration device.

FIG. 4 illustrates exemplary connections to an integrated meteringdevice.

FIG. 5 illustrates connections for a prior art system meter.

DETAILED DESCRIPTION

The invention provides an integrated metering device that allows aresource provider to control the output of a distributed generationdevice onto a resource distribution network or grid. The integratedmetering device may include a communications module and a metrologymodule, as well as an inverter and regulator device and a transferswitch. A resource provider may communicate with the integrated meteringdevice via the communications module and may control the inverter andregulator device or the transfer switch. The metrology module maymonitor the energy provided by the distributed generation device to thegrid and may send information about the generated energy to the resourceprovider via the communications module. The integrated metering devicesimplifies on-site wiring, enhances safety, provides one point ofutility communications and control, and prevents fraudulent connectionof non-approved distributed generation devices.

Exemplary Operating Environment

FIG. 1 illustrates an exemplary operating environment for an integratedmetering device. A network 100, such as a wireless mesh network,includes a number of nodes, 102-116, 120. Each nodes 102-116 may includea metrology module for measuring resource consumption at a customerpremises. The nodes may also include a communications module forcommunicating on the network using RF, cellular, PLC or any othersuitable communications technology. Some of the nodes, 108, 112, 116 maybe associated with an integrated metering device that controls the entryof a resource generated by a distributed generation device 132, 134, 136onto a utility grid (not shown) in addition to measuring consumption andcommunicating on the network. One example is the entry of electricenergy onto the electric grid. FIG. 1 illustrates that node 120 mayfurther communicate with other devices via network 140. In oneimplementation node 120 communicates with a head end system 150.

Integrated Metering Device

FIG. 2 illustrates an exemplary integrated metering device 200 for usewith a utility grid. The integrated metering device 200 connects thecustomer's premises to the grid and also connects a distributedgeneration device 230, such as an array of solar panels, to the grid.The integrated metering device integrates the functions of an inverterand regulator device, a transfer switch, a utility meter, and adistributed generation meter into a single device.

The output of the distributed generation device 230 is connected to aninput of the integrated metering device 200. The output may be connecteddirectly to the integrated metering device or may be connected to aseparate connector provided in an electric meter socket to which theintegrated meter is connected. For example, the output of thedistributed generation device may be a DC inverter output from an arrayof solar panels or an AC output from an AC generator. The integratedmeter is designed so that the output of the distributed generationdevice may be connected after the integrated meter is installed andproperly secured.

FIG. 4 illustrates a portion of an exemplary integrated metering devicethat includes terminals 412, 416 for connecting the distributedgeneration device and terminals 410, 414 for connecting to the customerpremises or load. Terminals 402 and 404 connect to the utility grid. Theintegrated metering device shown in FIG. 4 is similar to an ANSI Form 2Smeter, such as shown in FIG. 5, but it includes additional terminals andcircuitry for connecting to the distributed generation device. Note thatFIG. 4 does not illustrate all of the components of the integratedmetering device.

The inverter and regulator device 208 of the integrated metering deviceprocesses the output from the distributed generation device so that itmeets the requirements of the grid. For example, the inverter andregulator device may convert a DC output to AC, adjust the phase of theoutput, or regulate the output voltage to meet the requirements of thegrid. The output of the inverter and regulator device 208 is provided toa transfer switch 210. The transfer switch 210 connects the output ofthe distributed generation device to the utility grid. The transferswitch also prevents back feed power from the distributed generationdevice from entering the grid in the case of a power outage. During apower outage, back feed power may present a safety hazard to utilityworkers restoring power due to downed lines. Although FIG. 2 illustratesthat the transfer switch is located between the inverter and regulatordevice and the grid, it can be located elsewhere so long as it controlsthe flow of energy from the distributed generation device onto the grid.

The integrated metering device includes a metrology module 204 thatprovides metering functions. Exemplary metering functions includesmonitoring energy provided by the distributed generation device to theutility grid, monitoring energy used by the premises, and monitoring netenergy delivered to or received from the utility grid. The metrologymodule may include a single metering device or multiple meteringdevices. Metering information, including information on the energygenerated by a distributed generation device, may be provided to theutility via the communications module or displayed on an output deviceof the meter, such as a display device. The metrology module may alsomonitor characteristics of the energy provided by the distributedgeneration device or the utility grid including, but not limited to,wattage, VARs, or VA, harmonics or total harmonic distortion. Forexample, FIG. 2 illustrates that the metrology module monitors theoutput of the transfer switch 210. The metrology module may control thetransfer switch via switch control 206. For example, if the metrologymodule detects a loss of utility power, the metrology module may controlthe transfer switch to prevent power from the distributed generationdevice from entering the grid.

The metrology module may also control components of the inverter andregulator device. Exemplary actions include the following. If themetrology module senses an over-voltage or under-voltage condition, themetrology module may raise or lower the output voltage from the inverterto control the voltage. If the metrology module senses the voltage isover or under a configurable limit, the metrology module may disconnectfrom the grid. The metrology module may also disconnect the customerload if the voltage is over or under configurable limits for the load.The metrology module may use configurable limits for the amperagesupplied by the distributed generation device so that if the amperagesupplied by the distributed generation device exceeds the limit forsupplying the grid or the load, the metrology device may limit theamperage or shut down the distributed generation device.

The integrated metering device also includes communications module 202.The communications module may communicate with another device on thenetwork, such as a neighboring meter or a collector. The communicationsmodule may transmit information regarding the energy provided by thedistributed generation device to the utility grid, the energy used bythe premises, the net energy delivered to or received from the utilitygrid, the status of the device, or other information to the utility orto other devices on the network. The communications module may receivecommunications from the utility via the network that includeinstructions for controlling the inverter and regulator, the transferswitch, or the metrology module. In one example, a head end system sendsthe instructions to the communications module and the communicationsmodule controls the inverter, regulator, or switch components to controlthe power provided by the distributed generation device to the grid.

The communications module may control the inverter and regulator device.In some instances, the control is based on an instruction received bythe communications module. Exemplary instructions received by thecommunications module include the following:

-   -   Set Regulator Configuration (Specify regulator minimum and        maximum output voltage, maximum output current limit, minimum        grid voltage and duration time before opening the transfer        switch)    -   Get Regulator Configuration    -   Get Regulator Status (Regulator inverter input voltage, grid        output voltage, operation health status, voltage and current        limit status, transfer switch status)    -   Get Regulator Event History    -   Clear Regulator Event History    -   Distributed Energy Response (DER) Event—Limit current back onto        the grid to predefined DER limit. Communications module may        communicate to the regulator as well as to local intelligent        load control switches on the premises or to a group of load        control switches and other inverters that make up a local        micro-grid to limit the energy back onto the grid within a        predefined DER limit.

The communications module and the metrology module of the integratedmetering device may include one or more processing devices and memory.The processing devices may execute computer-executable instructionsstored on computer-readable media or access information stored oncomputer-readable media to perform the operations described herein.Although the communications module and the metrology module are shown asseparate modules in FIG. 2, the modules may be combined or may becombined with other components of the integrated metering device. Otherimplementations of the integrated metering device may use different oradditional modules and components than those illustrated in FIG. 2. Forexample, in one implementation the metrology module includes threemetering devices. One metering device is associated with the inverterand regulator device, a second metering device is associated with thepremises load, and a third metering device is a NET metering device thatmeasures the NET energy delivered to/received from the utility grid(e.g., difference between the energy measured at the inverter andregulator device and the energy consumed by the premises load). Eachmetering device may provide voltage, current, watt-hours, volt-amps,volt-amp-reactive or other measured parameter. In some implementations,the inverter and regulator device may include only an inverter or only aregulator depending upon the type of distributed generation device.

The communications module and the metrology module may control othercomponents of the integrated metering device via wired or wirelessconnections.

The housing for the integrated metering device may provide enhancedthermal management since the inverter and regulator components maydissipate more heat than the components of a conventional utility meter.Housings for conventional utility meters typically use plastic or glass,which are poor heat conductors. The housing for the integrated meteringdevice may include metal and may include metal fins to handle theadditional heat. In one example the housing includes aluminum fins.

The ability to remotely control the power provided by the distributedgeneration device by controlling components located at the premises isan improvement over the prior art. FIG. 3 illustrates a prior art systemthat includes two meters. A utility meter 300 is connected between theutility grid and the customer premises and a separate distributedgeneration meter 320 is connected between the distributed generationdevice and the utility meter.

The output of the distributed generation device 330 is connected to theinverter and regulator device 308. The output of the inverter andregulator device 308 is connected to the transfer switch 310. Thetransfer switch is also connected to the distributed generation meter320. Control of the inverter and regulator device 308 may be wired orwireless and may include controlling components within the device tomeet voltage and current set points and limits. The output of thedistributed generation meter 320 is connected to the premises side ofthe utility meter 300. The utility meter 300 is connected to the utilitygrid and the premises.

A head end system cannot communicate with the inverter and regulatordevice of FIG. 3. Although the head end system may send instructions toa communications module located in the utility meter 300, thecommunications module cannot provide instructions or otherwise controlthe inverter and regulator device or the transfer switch. Theconfiguration shown in FIG. 3 requires more physical space and isgenerally more expensive due to the need for more equipment andadditional labor. There is also a greater risk of tampering or improperwiring.

While the present subject matter has been described in detail withrespect to specific aspects thereof, it will be appreciated that thoseskilled in the art, upon attaining an understanding of the foregoing,may readily produce alterations to, variations of, and equivalents tosuch aspects. Accordingly, it should be understood that the presentdisclosure has been presented for purposes of example rather thanlimitation and does not preclude inclusion of such modifications,variations, and/or additions to the present subject matter as would bereadily apparent to one of ordinary skill in the art.

What is claimed is:
 1. A method for operating an integrated meteringdevice, comprising: connecting, by the integrated metering device, autility grid, a premises load, and a distributed generation device byproviding a grid interface for connecting to the utility grid, apremises interface for connecting to the premises load, and adistributed generation device interface for connecting to thedistributed generation device; monitoring, by a metrology module, energydelivered to the premises interface from the grid interface; receiving,by the distributed generation device interface, an output of thedistributed generation device; processing, by an inverter and regulatordevice, the output of the distributed generation device and providing aprocessed output from the inverter and regulator device to a transferswitch; controlling, by the metrology module, the transfer switch toprovide the processed output to the grid interface; monitoring, by themetrology module, energy delivered to the grid interface from thetransfer switch, and providing information on the energy delivered tothe grid interface from the transfer switch to a communications module;and communicating, by the communications module, a communication via anexternal network that includes the information on the energy deliveredto the grid interface from the transfer switch, wherein the inverter andregulator device, the transfer switch, the metrology module, and thecommunication module are located within a housing of the integratedmetering device.
 2. The method of claim 1, wherein monitoring, by ametrology module, energy delivered to the grid interface from thetransfer switch, comprises monitoring at least one characteristic of theenergy related to wattage, VARs, VA, harmonics, or total harmonicdistortion.
 3. The method of claim 1, wherein monitoring, by a metrologymodule, energy delivered to the grid interface from the transfer switch,comprises monitoring a voltage and based on the voltage controlling anoutput voltage of an inverter component within the inverter andregulator device.
 4. The method of claim 1, further comprising:receiving, by the communications module, an instruction via the externalnetwork; and controlling, by the communications module, the inverter andregulator device based on the instruction.
 5. The method of claim 4,wherein the instruction relates to a distributed energy response event,further comprising: communicating, by the communication module, withlocal load control switches to limit an amount of energy delivered tothe utility grid to a predefined limit.
 6. The method of claim 1,wherein processing, by an inverter and regulator device, the output ofthe distributed generation device comprises making a phase adjustment sothat a phase of the processed output is adjusted from a phase of theoutput of the distributed generation device.
 7. The method of claim 1,further comprising: detecting, by the metrology module, a loss ofutility power, and in response to detecting the loss of utility power,controlling the transfer switch to prevent power from the distributedgeneration device from entering the utility grid.
 8. The method of claim1, wherein the metrology module includes a first metering deviceassociated with the inverter and regulator device, a second meteringdevice associated with a premises load, and a third metering device thatis a NET metering device, further comprising: measuring, by the NETmetering device, net energy delivered to or received from the utilitygrid.
 9. A method for operating an integrated metering device,comprising: connecting, by the integrated metering device, a utilitygrid, a premises load, and a distributed generation device by providinga grid interface for connecting to the utility grid, a premisesinterface for connecting to the premises load, and a distributedgeneration device interface for connecting to the distributed generationdevice; monitoring, by a metrology module, energy delivered to thepremises interface from the grid interface; receiving, by thedistributed generation device interface, an output of the distributedgeneration device; processing, by an inverter and regulator device, theoutput of the distributed generation device and providing a processedoutput to a transfer switch; controlling, by a communication module, thetransfer switch to provide the processed output from the inverter andregulator device to the grid interface; monitoring, by the metrologymodule, energy delivered to the grid interface, and providinginformation on the energy delivered to the grid interface to thecommunications module; and communicating, by the communications module,a communication via an external network that includes the information onthe energy delivered to the grid interface, wherein the inverter andregulator device, the transfer switch, the metrology module, and thecommunication module are located within a housing of the integratedmetering device.
 10. The method of claim 9, wherein monitoring, by ametrology module, energy delivered to the grid interface, comprisesmonitoring at least one characteristic of the energy related to wattage,VARs, VA, harmonics, or total harmonic distortion.
 11. The method ofclaim 9, wherein monitoring, by a metrology module, energy delivered tothe grid interface, comprises monitoring a voltage and based on thevoltage controlling an output voltage of an inverter component withinthe inverter and regulator device.
 12. The method of claim 9, furthercomprising: receiving, by the communications module, an instruction viathe external network; and controlling, by the communications module, theinverter and regulator device based on the instruction.
 13. The methodof claim 12, wherein the instruction relates to a distributed energyresponse event, further comprising: communicating, by the communicationmodule, with local load control switches to limit an amount of energydelivered to the utility grid to a predefined limit.
 14. The method ofclaim 9, wherein processing, by an inverter and regulator device, theoutput of the distributed generation device comprises making a phaseadjustment so that a phase of the processed output is adjusted from aphase of the output of the distributed generation device.
 15. The methodof claim 9, further comprising: detecting a loss of utility power; andcontrolling the transfer switch to prevent power from the distributedgeneration device from entering the utility grid.
 16. An integratedmetering device, comprising: a housing; a grid interface, wherein thegrid interface includes a first plurality of terminals configured toconnect the integrated metering device to a utility grid; a premisesinterface; wherein the premises interface includes a second plurality ofterminals configured to connect the integrated metering device to apremises load; a distributed generation device interface, wherein thedistributed generation device interface includes a third plurality ofterminals configured to connect the integrated metering device to adistributed generation device; a regulator connected to the distributedgeneration device interface; a transfer switch connected to an output ofthe regulator and to the grid interface; a metrology module formeasuring energy delivered to the grid interface from the distributedgeneration device and energy delivered to the premises interface fromthe grid interface; and a communications module configured to receiveinstructions for controlling the regulator via an external network,wherein the regulator, the transfer switch, the metrology module and thecommunication module are located within the housing.
 17. The integratedmetering device of claim 16, further comprising: an inverter connectedbetween the distributed generation device interface and the regulator.18. The integrated metering device of claim 17, wherein the metrologymodule includes a first metering device associated with the regulatorand the inverter, a second metering device associated with the premisesload, and a third metering device configured to measure net energydelivered to or received from the utility grid.
 19. The integratedmetering device of claim 16, wherein the communications module isfurther configured to receive an instruction via the external networkand control the regulator based on the instruction.
 20. The integratedmetering device of claim 16, wherein the communications module isfurther configured to receive an instruction via the external networkand control the transfer switch based on the instruction.